δ13C Values of Grasses as a Novel Indicator of Pollution by Fossil-Fuel-Derived Greenhouse Gas CO2 in Urban Areas

Publisher Website
Google Scholar
Abstract
A novel fossil fuel pollution indicator based on the 13C/12C isotopic composition of plants has been designed. This bioindicator is a promising tool for future mapping of the sequestration of fossil fuel CO2 into urban vegetation. Theoretically, plants growing in fossil-fuel-CO2-contaminated areas, such as major cities, industrial centers, and highway borders, should assimilate a mixture of global atmospheric CO2 of δ13C value of −8.02‰ and of fossil fuel CO2 of average δ13C value of −27.28‰. This isotopic difference should, thus, be recorded in plant carbon. Indeed, this study reveals that grasses growing near a major highway in Paris, France, have strikingly depleted δ13C values, averaging at −35.08‰, versus rural grasses that show an average δ13C value of −30.59‰. A simple mixing model was used to calculate the contributions of fossil-fuel-derived CO2 to the plant tissue. Calculation based on contaminated and noncontaminated isotopic end members shows that urban grasses assimilate up to 29.1% of fossil-fuel-CO2-derived carbon in their tissues. The 13C isotopic composition of grasses thus represents a promising new tool for the study of the impact of fossil fuel CO2 in major cities.